1. Technical Field of the Invention
The present invention relates to an optical disc apparatus, specially relates to control of recording power when information recording is performed.
2. Description of the Related Art
As to an optical disc apparatus, an increase in the laser output is demanded with increasing recording speed, resulting in a reduced output margin. This makes it more difficult to stabilize the output in a high-temperature environment. Conventionally, a technology of suppressing the influence of the variation in the laser output to the control current of a laser diode has been implemented to obtain a stable recording quality; and new technologies are also under consideration. With high-speed recording of DVD, for example, so-called running OPC (Optimum Power Control) and walking OPC are implemented in order to control the laser output at the time of recording. In running OPC, the intensity of returned light (reflected laser beams) of laser beams applied to an optical disc for information recording is detected and the laser output is corrected based on the detection result. In walking OPC, recording operation is periodically stopped, the recording quality of the signal recorded immediately before the stop of operation is measured, and the laser output is corrected based on the measurement result.
Technologies of ensuring the recording quality are described, for example, in JP-A-2005-222676 and JP-A-2006-114166. In order to perform stable recording to an optical disc with an excellent recording quality, JP-A-2005-222676 describes a technology of performing OPC (Optimum Power Control) again based on the elapsed time since last OPC or temperature information if recording at a zone changeover position with the ZCLV (Zone Constant Linear Velocity) method is suspended. JP-A-2006-114166 describes a technology of recording information with the PCAV (Partial Constant Angular Velocity) method in an optical disc apparatus, the technology comprising the steps of: first performing trial write operation to an inner circumference of an optical disc; moving an optical pickup toward the outer circumference of the disc; if a maximum amplitude of a focus error signal and a tracking error signal reaches or exceeds a threshold value, decelerating a maximum recording speed so that the maximum amplitude become less than the threshold value and setting an information recording speed; and setting recording power for information recording based on the power information obtained in the above-mentioned trial write operation, wherein trial write operation is performed on the outer circumference of the optical disc only in the case of 16× speed recording in which decelerated recording is not required.